Display device

ABSTRACT

Provided is a display device characterized in that the electric power consumption when optical modulation elements (for example, MEMS shutters) are driven is reduced: A display device ( 1000 ) includes a backlight unit ( 1 ), a display panel unit ( 2 ), a source driver ( 3 ), and a controller ( 4 ). The backlight unit ( 1 ) includes a light source. The display panel unit ( 2 ) includes segmented pixel regions AR 11  to ARnm each of which includes: a plurality of pixels each of which includes an optical modulation element that performs modulation control with respect to light projected from the backlight unit ( 1 ); and a segmented gate driver that controls the optical modulation elements of the pixels. The source driver ( 3 ) is a driver that controls the optical modulation elements of the pixels. The controller ( 4 ) controls the light source of the backlight unit ( 1 ), the segmented gate drivers GD 11  to GDnm, and the source driver ( 3 ).

TECHNICAL FIELD

The present invention relates to a display device that displays an image(a video image), and in particular, relates to a technique forcontrolling optical modulation elements incorporated in a displaydevice.

BACKGROUND ART

A display device in which MEMS (Micro Electro Mechanical Systems)shutters are used as optical modulation elements is known (hereinaftersuch a display device is referred to as a “MEMS shutter display device”)(see, for example, Patent Document 1 (JP-A-2013-50720)). The MEMSshutter is, for example, a shutter realized by the MEMS technique (anelement (structure) that controls transmission and/or cutoff of light),as disclosed in Patent Document 1.

In such a MEMS shutter display device, unlike a liquid crystal displaydevice, there is no need to provide color filters or polarizing plates.In the MEMS shutter display device, therefore, the rate of transmissionof the light from the backlight can be increased, which allows electricpower for emitting light from the backlight to be reduced significantly.

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

In the MEMS shutter display device, however, it is necessary to drivethe MEMS shutters with driving signals having higher frequencies, ascompared with a liquid crystal display device. In the MEMS shutterdisplay device, an image is displayed by a field sequential colorsystem. Further, in the MEMS shutter display device, each pixel isprovided with a MEMS shutter, and the gray level value of each pixel isexpressed by adjusting the open/close time of the MEMS shutter providedin each pixel. In the MEMS shutter display device, therefore, as thenumber of gray level values (or the number of colors, the number ofbits) to be expressed by each pixel increases, the MEMS shutter has tobe driven with a driving signal having a higher frequency. In otherwords, in the MEMS shutter display device, in a case where a greaternumber of the gray level values (or the number of colors, the number ofbits) are to be expressed by each pixel, an increase in the electricpower consumption is a problem to be solved.

Then, in light of the above-described problem, it is an object of thepresent invention to provide a display device in which, the electricpower consumption to drive optical modulation elements (for example,MEMS shutters) is reduced.

Means to Solve the Problem

To solve the above-described problem, the first configuration is adisplay device that includes a backlight unit, a display panel unit, asource driver, and a controller.

The backlight unit includes a light source.

The display panel unit includes a plurality of first segmented regions,each of the first segmented regions including: a plurality of pixelseach of which includes an optical modulation element that performsmodulation control with respect to light emitted from the backlightunit: and a segmented gate driver for controlling the optical modulationelements of the pixels.

The source driver is a driver for controlling the optical modulationelements of the pixels.

The controller controls the light source, the segmented gate drivers,and the source driver.

EFFECT OF THE INVENTION

With the present invention, it is possible to provide a display devicein which the electric power consumption when the optical modulationelements (for example, MEMS shutters) are driven is reduced.

BRIEF DESCRIPTION OF DRAWINGS

[FIG. 1] FIG. 1 illustrates a schematic configuration of a displaydevice 1000 according to Embodiment 1.

[FIG. 2] FIG. 2 illustrates a schematic configuration of a source driver3, and segmented pixel regions AR11, AR12.

[FIG. 3] FIG. 3 illustrates a schematic configuration of an opticalmodulation element portion MS1 in a case where light from a backlightunit 1 is projected to outside.

[FIG. 4] FIG. 4 illustrates a schematic configuration of the opticalmodulation element portion MS1 in a case where light from the backlightunit 1 is not projected to outside.

[FIG. 5] FIG. 5 is a timing chart (example) that illustrate therelationship among a backlight control signal CTL_BL, display data(image data) Din, a source driving signal V_S1 (a source driving signaloutput via a source line S1), and a source driving signal V_S2 (a sourcedriving signal output via a source line S2) in a case where the displaydevice 1000 is caused to display image data.

[FIG. 6] FIG. 6 is a timing chart (example) that illustrate therelationship among the backlight control signal CTL_BL, display data(image data) Din, the source driving signal V_S1 (the source drivingsignal output via the source line S1), and the source driving signalV_S2 (the source driving signal output via the source line S2) in a casewhere the display device 1000 is caused to display image data.

[FIG. 7] FIG. 7 illustrates a schematic configuration of a displaydevice 2000 of Embodiment 2.

[FIG. 8] FIG. 8 illustrates a schematic configuration of a displaydevice 3000 of Embodiment 3.

[FIG. 9] FIG. 9 is a diagram for explaining a controlling operation in acase where regions segmented in the horizontal direction are set, andthe gate driving is performed with respect to the regions segmented inthe horizontal direction simultaneously.

MODE FOR CARRYING OUT THE INVENTION Embodiment 1

The following description describes Embodiment 1, while referring to thedrawings.

<1.1: Configuration of Display Device>

FIG. 1 illustrates a schematic configuration of a display device 1000according, to Embodiment 1.

FIG. 2 illustrates a schematic configuration of a source driver 3 andsegmented pixel regions AR11, AR12.

FIG. 3 illustrates a schematic configuration of an optical modulationelement portion MS1 in a case where light from a backlight unit 1 isprojected to outside. The upper diagram of FIG. 3 is a schematiccross-sectional view taken along the line A-A in the lower diagram inFIG. 3.

FIG. 4 illustrates a schematic configuration of the optical modulationelement portion MS1 in a case where light from the backlight unit 1 isnot projected to outside. The upper diagram of FIG. 4 is a schematiccross-sectional view taken along the line A-A in the lower diagram inFIG. 4.

The display device 1000 includes the backlight unit 1, a display panelunit 2, a source driver 3, and a controller 4, as illustrated in, FIG.1.

The backlight unit 1 includes a light source (not illustrated), andprojects light emitted from the light source to the display panel unit2. The light source is composed of, for example, a red colorlight-emitting diode, a green color light-emitting diode, and a bluecolor light-emitting diode. The light source of the backlight unit 1 iscontrolled according to a backlight control signal CTL_BL sent form thecontroller 4.

The display panel unit 2 includes segmented pixel regions AR11 to ARnm,the number of which is n×m (n, m: natural numbers), as illustrated inFIG. 1.

Each segmented pixel region includes a segmented gate driver and aplurality of pixels, as illustrated in FIGS. 1 and 2. One pixel includesa switching element SWk (k: natural number) and an optical modulationelement portion MSk (k: natural number), as illustrated in FIG. 2. Theswitching element SWk is, for example, a thin film transistor (TFT)element.

For convenience of description, a case where one segmented pixel regionincludes one segmented gate driver and eight pixels is described.Further, in the description, it is assumed that the switching elementSWk is a thin film transistor (TFT) element.

The configuration of the segmented pixel region is described withreference to a segmented pixel region AR11 illustrated in FIG. 2 as anexample.

The segmented pixel region AR11 includes a segmented gate driver GD11and eight pixels, as illustrated in FIG. 2. For convenience sake, theeight segmented pixels in pixel region AR11 in FIG. 2 are referred to asfirst to eighth pixels, and are denoted by Px1 to Px8, respectively. Thek-th pixel Pxk (k: natural number, 1≦k≦8) is a pixel that includes aswitching element SWk and an optical modulation element portion MSk.

Hereinafter, the switching element SWk of the k-th pixel in thesegmented pixel region AR11 is denoted as “SWk(AR11)”, and the opticalmodulation element portion MSk of the k-th pixel in the segmented pixelregion AR11 is denoted as “MSk(AR11)”.

The segmented gate driver GD11 is connected to the gate of the switchingelement SWk of each pixel via four gate lines GL1 to GL4, as illustratedin FIG. 2. The segmented gate driver GD11 inputs a gate control signalCTL_G output from the controller 4. The segmented gate driver GD11outputs the gate driving signal via the gate lines at predeterminedtimings based on the gate control signal CTL_G, thereby turning on theswitching element SWk of each pixel.

As illustrated in FIG. 2, the first pixel Px1 includes a switchingelement SW and an optical modulation element portion MS1.

As illustrated in FIG. 2, the switching element SW1 has such aconfiguration that the source thereof is connected via the source lineS1 to the source driver 3. Further, the drain of the switching elementSW1 is connected to the optical modulation element portion MS1.

As illustrated in FIG. 3, the optical modulation element portion MS1 isarranged on a display surface side (cover layer 22 side) of an openingpart ap1 provided in a light-shielding layer 21 formed in an upper part(display surface side) of the backlight unit 1. As illustrated in FIG.3, the optical modulation element portion MS1 includes a first electrodeex1, a second electrode ex2, a shutter portion st1, and an elasticportion sp1.

As illustrated in FIG. 3, the first electrode ex1 is connected to thedrain of the switching element SW1. The first electrode ext for example,is fixed to the cover layer 22, as illustrated in FIG. 3. The firstelectrode ex1 comes to have a positive potential, when, for example, theswitching element SW1 is turned on in response to a gate driving signal,and an electric current (source driving electric current) correspondingto the source driving signal flows via the source line S1 from theswitching element SW1 to a resistance R1. In other words, in this case,the first electrode ex1 is in a state where positive charges are held.

Further, when the switching element SW1 is in an off state, or when thesource driving electric current does not flow from the switching elementSW1 to the resistance R1, the first electrode ex1 has a zero potential(GND potential). In other words, in this case, the first electrode ex1is in a state where no charge is kept.

As illustrated in FIG. 3, when viewed in a plan view, the secondelectrode ex2 is arranged so that the opening part ap1 is interposedbetween the second electrode ex2 and the first electrode ex1. The secondelectrode ex2, for example, is fixed to the cover layer 22 asillustrated in FIG. 3. Further, the second electrode ex2 is connectedwith the elastic portion sp1 as illustrated in FIG. 3. The secondelectrode ex2, for example, is connected to a power source having anegative potential or the like via a resistance (not illustrated) so asto have a negative potential, for example.

The shutter portion st1 is made of a light-blocking material, and has anopening for allowing light from the backlight unit 1 to passtherethrough, as illustrated in FIG. 3. Further, the shutter portion st1is connected with the elastic portion sp1, which is conductive. Theshutter portion st1 is connected with the second electrode ex2 having anegative potential, via the elastic portion sp1, thereby having anegative potential. In other words, in a case where the second electrodeex2 has a negative potential, the shutter portion st1 is in a statewhere negative charges are held.

The elastic portion sp1 is made of a conductive material, and isconnected to the shutter portion st1 and the second electrode ex2. Theelastic portion sp1 has elasticity, and assumes a state illustrated inFIG. 3 (a state where the shutter is closed), when no electromagneticforce is exerted between the shutter portion st1 and the first electrodeex1.

Further, in a case where charges held in the first electrode ex1 andcharges held in the shutter portion st1 are different, the elasticportion sp1 assumes a state illustrated in FIG. 4 (a state where theshutter is open), due to an attractive force exerted between the firstelectrode ex1 and the shutter portion st1.

In this way, in the optical modulation element portion MS1, by causingthe switching element SW1 to be turned on so as to cause a sourcedriving electric current to flow, the first electrode ex1 can be chargedpositively, which causes the negatively charged shutter portion st1 tomove so as to shift into a state illustrated in FIG. 4. In other words,by doing as described above, the shutter can be caused to shift to anopen state. When the optical modulation element portion MS1 assumes thisstate, the light from the backlight unit 1 is caused to pass through thesame toward the outside.

On the other hand, in the optical modulation element portion MS1, byturning the switching element SW1 off, or causing the source drivingelectric current not to flow, the first electrode ex1 is caused to havea zero potential, whereby the electromagnetic force exerted between thefirst electrode ex1 and the shutter portion st1 is caused to disappear.This allows the shutter portion st1 to return to the position of thesteady state illustrated in FIG. 3.

The optical modulation element portion MS1 of the first pixel Px1 hasthe configuration as described above.

The second to eighth pixels Px2 to Px8 have configurations identical tothat of the first pixel Px1 described above.

source driver 3 inputs a source control signal CTL_S output from thecontroller 4 and display data D1 output from the controller 4, asillustrated in FIG. 1. The source driver 3 generates source drivingsignals for source lines S1 to Sm, respectively, based on the sourcecontrol signal CTL_S and the display data D1, and outputs the generatedsource driving signals via the source lines S1 to Sm to the displaypanel unit 2.

The controller 4 outputs, to the backlight unit 1, a backlight controlsignal CTL_BL for controlling the light emission of the backlight of thebacklight unit 1.

Further, the controller 4 outputs, to the segmented gate drivers GD11 toGDnm of the display panel unit 2, a gate control signal for controllingthe segmented gate drivers GD11 to GDnm of the display panel unit 2.

Further, the controller 4 outputs the display data D1 to be displayed bythe display panel unit 2, to the source driver 3.

<1.2: Operation of Display Device

The following description describes operations of the display device1000 having a configuration as described above.

FIGS. 5 and 6 are timing, charts (examples) that illustrate therelationship among a backlight control signal CTL_BL, display data(image data) Din, a source driving signal V_S1 (a source driving signaloutput via the source line S1), and a source driving signal V_S2 (asource driving signal output via the source line 52) in a case where thedisplay device 1000 is caused to display image data.

While referring to FIGS. 5 and 6, the following description describes,as an example, a case where, in the display device 1000, color data of24 bits in total, composed of R component 8-bit data, G component 8-bitdata, and B component 8-bit data (color data of R, G, B at 256 graylevels each) are displayed by the field sequential color method at eachpixel.

More specifically, as an example, a case is described where

(1) in a first frame, a gray level value of “180” of the R component, agray level value of “110” of the a G component, and a gray level valueof “128” of the B component are displayed at a first pixel Px1 in asegmented pixel region AR11 (this pixel is denoted as “Px1(AR11)”), and

(2) in the first frame, a gray level value of “53” of the R component, agray level value of “194” of the G component, and a gray level value of“53” of the B component are displayed at a second pixel Px2 in asegmented pixel region AR11 (this pixel is denoted as “Px2(AR11)”).

<<Display of R Component Image (Subframe Image)>>

(Period from t1 to t11);

During a period from time t1 to time t11, the controller 4 outputs, tothe backlight unit 1, a backlight control signal CTL_BL that instructsthe light source of the backlight unit 1 to shift to a state of beingturned off. The backlight unit 1 causes the light source of thebacklight unit 1 to shift to a state of being turned off, based on thebacklight control signal CTL_BL from the controller 4.

The controller 4 outputs, to the source driver 3, image data Din thatare to be displayed as a first frame image. More specifically, thecontroller 4 outputs, to the source driver 3, a red color componentimage (hereinafter referred to as “R component image”) of the firstframe image that is to be displayed during a first subframe period of afirst frame. It should be noted that one frame image is assumed to becomposed of a red color component image, a green color component image(hereinafter referred to as “G component image”), arid a blue colorcomponent image (hereinafter referred tows “B component image”).

Based on the pixel value of each pixel of the R component image of thefirst frame, the controller 4 decides an initial state of the shutterportion st1 of the optical modulation element portion of each pixel inthe display panel unit 2, and controls the source driver 3 with thesource control signal CTL_S so that the decided initial state isachieved.

More specifically, the controller 4 controls the source driver 3 withthe source control signal CTL_S, so as to: (1) cause the opticalmodulation element portion of the pixel in the display panel unit 2corresponding to a pixel having a pixel value of “0” as the pixel valueof the R component image in the first frame to shift to a state wherethe shutter is closed; and (2) cause the optical modulation elementportion of the pixel in the display panel unit 2 corresponding to apixel having a pixel value of not “0” as the pixel value of the Rcomponent image in the first frame to shift to a state where the shutteris open.

Further, in order that all of the pixels in the display panel unit 2shift to the decided initial state as described above, the controller 4outputs the gate control signal CTL_G for controlling the segmented gatedrivers GD11 to GDnm in the display panel unit 2, to the segmented gatedrivers GD11 to GDnm in the display panel unit 2. More specifically, thecontroller 4 controls the segmented gate drivers GD11 to GDnm so thatthe same output a gate driving signal so that switching elements of thepixels of the respective lines in the display panel unit 2 are turned online-sequentially (or point-sequentially).

The source driver 3 and the segmented gate drivers GD11 to GDnm arecontrolled by the controller 4 in this way, whereby the opticalmodulation element portions of all of the pixels in the display panelunit 2 are set to the initial state, In other words, the initial stateis set so that: (1) the optical modulation element portion of the pixelin the display panel unit 2 corresponding to a pixel having a pixelvalue of “0” as the pixel value of the R component image in the firstframe shifts to a state where the shutter is closed; and (2) the opticalmodulation element portion of the pixel in the display panel unit 2corresponding to a pixel having a pixel value of not “0” as the pixelvalue of the R component image in the first frame shifts to a statewhere the shutter is open.

Incidentally, in FIGS. 5 and 6, the periods from t1 to t11, from t2 tot21, from t3 to t31, and from t4 to t41 for setting the opticalmodulation element portions of all of the pixels in the display panelunit 2 are illustrated as periods shorter than actual periods, for wantof space.

The reason why the light source of the backlight unit 1 is in a state ofbeing turned off while the optical modulation element portions of all ofthe pixels in the display panel unit 2 are set to the initial state isas follows: if the light source of the backlight unit 1 is turned onwhen the shutter portion st1 of the optical modulation element portionis performing an opening/closing operation, the brightness of an image(video image) displayed on the display panel unit 2 is visuallyrecognized as if it changed, due to the light emitted from the displaypanel unit 2 during the opening/closing operation of the shutter portionst1 of the optical modulation element portion, and this adverselyaffects the display quality (in particular, the hue).

(Period from t11 to t13):

At time t11, the controller 4 outputs, to the backlight unit 1, thebacklight control signal CTL_BL that instructs the backlight unit 1 toturn on the light source (the light source that emits red color light),so as to shift to a state where red color light is projected. Based onthe backlight control signal CTL_BL from the controller 4, the backlightunit 1 turns on the light source (the light source that emits red colorlight) of the backlight unit 1. This state (the state where the lightsource of red color light is turned on so that the red color light isemitted) is maintained during a period from t11 to t2.

At time t11, the segmented gate driver GD11 outputs a gate drivingsignal via the gate line GL1 so as to turn on the switching element SW1.Then, the source driver 3 outputs a source driving signal (a sourcedriving voltage V_S1) via the source line S1 during the period from t11to t12 so that the source driving electric current flows through theswitching element SW1 and the resistance R1. This allows the opticalmodulation element portion MS1 of the first pixel Px1 in the segmentedpixel region AR11 maintains the state where the shutter portion st1 isopen during the period from t11 to t12.

At time t12, the source driver 3 stops the output of the source drivingsignal (for example, shifts the source driving voltage V_S1 to 0V), soas to, cause the first electrode ex1 of the optical modulation elementportion MS1 of the first pixel Px1 to have a potential of 0V (the GNDpotential). This causes the attractive force exerted between the firstelectrode ex1 and the shutter portion st1 charged negatively todisappear, whereby the shutter portion st1 returns to the stateillustrated in FIG. 3, and the optical modulation element portion MS1 ofthe first pixel Px1 shifts to the state where the shutter is closed.

Here, the period from t11 to t12 and the period from t11 to t13 have thefollowing relationship in a case where the gray level value and theamount of light are in a relation of proportion:

(Period from t11 to t12)/(Period from t11 to t13)= 180/255

Further, the periods from t1 to t13, from t13 to t15, from t21 to t23,from t23 to t25, from t31 to t33, from t33 to t35, from t41 to t42, andt42 to t44 are periods of the same duration, and a gray level value of“255” can be expressed when a state where the shutter is open ismaintained throughout this period.

As described above, with a controlling operation that causes, in thefirst pixel Px1, a state where the shutter is open to be maintained onlyduring the period from t11 to t12, and causes the red color light to beprojected from the first pixel Px1 to outside, a R component gray levelvalue of “180” can be expressed at the first pixel Px1.

(Period from t13 to t15):

At time t13, the segmented gate driver GD11 outputs the gate drivingsignal so that the switching element SW2 is turned on, via the gate lineGL1. During a period from time t11 to time t15, the segmented gatedriver GD11 may output the gate driving signal so that the switchingelements SW1, SW2 are turned on, via the gate line GL1.

The source driver 3 outputs the source driving signal (the sourcedriving voltage V_S2) via the source line S2 during a period from t13 tot14, so that a source driving electric current flows through theswitching element SW2 and a resistance R2 (a resistance R2 (notillustrated) that is connected to the drain of the switching element SW2and the first electrode ex1 of the second pixel Px2, with the sameconfiguration as that of FIG. 3). This causes the optical modulationelement portion MS2 of the second pixel Px2 in the segmented pixelregion AR11 to maintain the state where the shutter portion st1 is open,during the period from t13 to t14.

At time t14, the source driver 3 stops the output of the source drivingsignal (for example, shifts the source driving voltage V_S2 to 0V), soas to cause the first electrode ex1 of the optical modulation elementportion MS2 of the second pixel Px2 to have a potential of 0V (the GNDpotential). This causes the attractive force exerted between the firstelectrode ex1 and the shutter portion st1 charged negatively disappear,whereby the shutter portion st1 returns to the state illustrated in FIG.3, and the optical modulation element portion MS1 of the second pixelPx2 shifts to the state where the shutter is closed.

Here, the period from t13 to t14 and the period from t13 to t15 have thefollowing relationship in a case where the gray level value and theamount of light are in a relation of proportion:

(Period from t13 to t14)/(Period from t13 to t15)= 53/255

As described above, with a controlling operation that causes, in thesecond pixel Px2, a state where the shutter is open is maintained onlyduring the period from t13 to t14, and the red color light is projectedfrom the second pixel Px2 to outside, a R component gray level value of“53” can be expressed at the second pixel Px2,

Likewise, controlling operations identical to that described above areperformed so that predetermined R component gray level values areexpressed at the third pixel Px3 and the fourth pixel Px4 in thesegmented pixel region AR11.

Further, controlling operations identical to that described above areperformed so that predetermined R component gray level values areexpressed at the first to fourth pixels in the segmented pixel regionAR12, the first to fourth pixels in the segmented pixel region AR13, . .. and the first to fourth pixels in the segmented pixel region AR1m.

Thus, the driving with respect to the pixels on the first line of thedisplay panel unit 2 is completed.

Next, the pixels on the second line are driven by identical controllingoperations.

More specifically, controlling operations identical to that describedabove are performed so that predetermined R component gray level valuesare expressed at the fifth to eights pixels in the segmented pixelregion AR11, the fifth to eight pixels in the segmented pixel regionAR12, and the fifth to eighth pixels in the segmented pixel region AR1m.

Likewise, the pixels on the third and fourth lines are driven byperforming controlling operations identical to that described above inthe segmented pixel regions AR21 to AR2m.

The same processing is applied to the subsequent lines, whereby all ofthe pixels in the display panel unit 2 are driven in the same manner.With this, during the first subframe period from t1 to t2, the Rcomponent subframe image is displayed by the display panel unit 2.

<<Display of G Component Image (Subframe Image)>>

(Period from t2 to t21):

During a period from time t2 to time t21, the controller 4 outputs, tothe backlight unit 1, a backlight control signal CTL_BL that instructsthe light source of the backlight unit 1 to shift to a state of beingturned off. The backlight unit 1 causes the light source of thebacklight unit 1 to shift to a state of being turned off, based on thebacklight control signal CTL_BL from the controller 4.

The controller 4 outputs, to the source driver 3, image data Din thatare to be displayed as a first frame image. More specifically, thecontroller 4 outputs, to the source driver 3, a G component image of thefirst frame image that is to be displayed during a second subframeperiod of the first frame.

Based on the pixel value of each pixel of the G component image of thefirst frame, the controller 4 decides an initial state of the shutterportion st1 of the optical modulation element portion of each pixel inthe display panel unit 2, and controls the source driver 3 with thesource control signal CTL_S so that the decided initial state isachieved.

More specifically, the controller 4 controls the source driver 3 withthe source control signal CTL_S, so as to: (1) cause the opticalmodulation element portion of, the pixel in the display panel unit 2corresponding to a pixel having a pixel value of “0” as the pixel valueof the G component image in the first frame to shift to a state wherethe shutter is closed; and (2) cause the optical modulation elementportion of the pixel in the display panel unit 2 corresponding to apixel having a pixel value of not “0” as the pixel value of the Gcomponent image in the first frame to shift to a state where the shutteris open.

Further, in order that all of the pixels in the display panel unit 2shift to the decided initial state as described above, the controller 4outputs the gate control signal CTL_G for controlling the segmented gatedrivers GD11 to GDnm in the display panel unit 2, to the segmented gatedrivers GD11 to GDnm in the display panel unit 2. More specifically, thecontroller 4 controls the segmented gate drivers GD11 to GDnm so thatthe same output a gate driving signal so that switching elements of thepixels of the respective lines in the display panel unit 2 are turned online-sequentially (or point-sequentially).

The source driver 3 and the segmented gate drivers GD11 to GDnm arecontrolled by the controller 4 in this way, whereby the opticalmodulation element portions of all of the pixels in the display panelunit 2 are set to the initial state. In other words, the initial stateis set so that (1) the optical modulation element portion of the pixelin the display panel unit 2 corresponding to a pixel having a pixelvalue of “0” as the pixel value of the G component image in the firstframe shifts to a state where the shutter is closed; and (2) the opticalmodulation element portion of the pixel in the display panel unit 2corresponding to a pixel having a pixel value of not “0” as the pixelvalue of the G component image in the first frame shifts to a statewhere the shutter is open.

(Period from t21 to t23):

At time t21, the controller 4 outputs, to the backlight unit 1, thebacklight control signal CTL_BL that instructs the backlight unit 1 toturn on the light source (the light source that emits green colorlight), so as to shift to a state where green color light is projected.Based on the backlight control signal CTL_BL from the controller 4, thebacklight unit 1 turns on the light source (the light source that emitsgreen color light) of the backlight unit 1. This state (the state wherethe light source of green color light is turned on so that the greencolor light is emitted) is maintained during a period from t21 to t3.

At time t21, the segmented gate driver GD11 outputs a gate drivingsignal via the gate line GL1 so as to turn on the switching element SW1.Then, the source driver 3 outputs a source driving signal (a sourcedriving voltage V_S1) via the source line S1 during the period from t21to t22 so that the source driving electric current flows through theswitching element SW1 and the resistance R1. This allows the opticalmodulation element portion MS1 of the first pixel Px1 in the segmentedpixel region AR11 maintains the state where the shutter portion st1 isopen during the period from t21 to t22.

At time t22, the source driver 3 stops the output of the source drivingsignal (for example, shifts the source driving voltage VS1 to 0V), so asto cause the first electrode ex1 of the optical modulation elementportion MS1 of the first pixel Px1 to have a potential of 0V (the GNBpotential). This causes the attractive force exerted between the firstelectrode ex1 and the shutter portion st1 charged negatively todisappear, whereby the shutter portion st1 returns to the stateillustrated in FIG. 3, and the optical modulation element portion MS1 ofthe first pixel Px1 shifts to the state where the shutter is closed.

Here, the period from t21 to t22 and the period from t21 to t23 have thefollowing relationship in a case where the gray level value and theamount of light are in a relation of proportion:

(Period from t21 to t22)/(Period from t21 to t23)= 110/255

As described above, with a controlling operation that causes, in thefirst pixel Px1, a state where the shutter is open is maintained onlyduring the period from t21 to t22, and the green color light isprojected from the first pixel Px1 to outside, a G component gray levelvalue of “110” can be expressed at the first pixel Px1.

(Period from t23 to t25):

At time t23, the segmented gate driver GD11 outputs the gate drivingsignal so that the switching element SW2 is turned on, via the gate lineGL1. During a period from time t21 to time t25, the segmented gatedriver GD11 may output the gate driving signal so that the switchingelements SW1, SW2 are turned on, via the gate line GL1.

The source driver 3 outputs the source driving signal (the sourcedriving voltage V_S2) via the source line S2 during a period from t23 tot24, so that a source driving electric current flows through theswitching element SW2 and a resistance R2 (a resistance R2 (notillustrated) that is connected to the drain of the switching element SW2and the first electrode ex1 of the second pixel Px2, with the sameconfiguration as that of FIG. 3). This causes the optical modulationelement portion MS2 of the second pixel Px2 in the segmented pixelregion AR11 to maintain the state where the shutter portion st1 is open,during the period from t23 to t24.

At time t24, the source driver 3 stops the output of the source drivingsignal (for example, shifts the source driving voltage V_S2 to 0V), soas to cause the first electrode ex1 of the optical modulation elementportion MS2 of the second pixel Px2 to have a potential of 0V (the GNBpotential). This causes the attractive force exerted between the firstelectrode ex1 and the shutter portion st1 charged negatively disappear,whereby the shutter portion st1 returns to the state illustrated in FIG.3, and the optical modulation element portion MS1 of the second pixelPx2 shifts to the state where the shutter is closed.

Here, the period from t23 to t24 and the period from t23 to t25 have thefollowing relationship in a case where the gray level value and theamount of light are a relation of proportion:

(Period from t23 to t24)/(Period from t23 to t25)= 194/255

As described above, with a controlling operation that causes, in thesecond pixel Px2, a state where the shutter is open is maintained onlyduring the period from t23 to t24, and the green color light isprojected from the second pixel Px2 to outside, a G component gray levelvalue of “194” can be expressed at the second pixel Px2.

Likewise, controlling operations identical to that described above areperformed so that predetermined G component gray level values areexpressed at the third pixel Px3 and the fourth pixel Px4 in thesegmented pixel region AR11.

Further, controlling operations identical to that described above areperformed so that predetermined G component gray level values areexpressed at the first to fourth pixels in the segmented pixel regionAR12, the first to fourth pixels in the segmented pixel region AR13, . .. and the first to fourth pixels in the segmented pixel region AR1m.

Thus, the driving with respect to the pixels on the first line of thedisplay panel unit 2 is completed.

Next, the pixels on the second line are driven by identical controllingoperations.

More specifically, controlling operations identical to that describedabove are performed so that predetermined G component gray level valuesare expressed at the fifth to eights pixels in the segmented pixelregion AR11 the fifth to eight pixels in the segmented pixel regionAR12, . . . and the fifth to eighth pixels in the segmented pixel regionAR1m.

Likewise, the pixels on the third and fourth lines is driven byperforming controlling operations identical to that described above inthe segmented pixel regions AR21 to AR2m.

The same processing is applied to the subsequent lines, whereby all ofthe pixels in the display panel unit 2 are driven in the same manner.With this, during the second subframe period from t2 to t3, the Gcomponent subframe image is displayed by the display panel unit 2.

<<Display of B Component Image (Subframe Image)>>

(Period from t3 to t31):

During a period from time t3 to time t31, the controller 4 outputs, tothe backlight unit 1, a backlight control signal CTL_BL that instructsthe light source of the backlight unit 1 to shift to a state of beingturned off. The backlight unit 1 causes the light source of thebacklight unit 1 to shift to a state of being turned off, based on thebacklight control signal CTL_BL from the controller 4.

The controller 4 outputs, to the source driver 3, image data Din thatare to be displayed as a first frame image. More specifically, thecontroller 4 outputs, to the source driver 3, a B component image of thefirst frame image that is to be displayed during a third subframe periodof the first frame.

Based on the pixel value of each pixel of the B component image of thefirst frame, the controller 4 decides an initial state of the shutterportion st1 of the optical modulation element portion of each pixel inthe display panel unit 2, and controls the source driver 3 with thesource control signal CTL_S so that the decided initial state isachieved.

More specifically, the controller 4 controls the source driver 3 withthe source control signal CTL_S, so as to: (1) cause the opticalmodulation element portion of the pixel in the display panel unit 2corresponding to a pixel having a pixel value of “0” as the pixel valueof the B component image in the first frame to shift to a state wherethe shutter is closed; and (2) cause the optical modulation elementportion of the pixel in the display panel unit 2 corresponding to apixel having a pixel value of not “0” as the pixel value of the Bcomponent image in the first frame to shift to a state where the shutteris open.

Further, in order that all of the pixels in the display panel unit 2shift to the decided initial state as described above, the controller 4outputs the gate control signal CTL_G for controlling the segmented gatedrivers GD11 to GDnm in the display panel unit 2, to the segmented gatedrivers GD11 to GDnm in the display panel unit 2. More specifically, thecontroller 4 controls the segmented gate drivers GD11 to GDnm so thatthe same output a gate driving signal so that switching elements of thepixels of the respective lines in the display panel unit 2 are turned online-sequentially (or point-sequentially),

The source driver 3 and the segmented gate drivers GD11 to GDnm arecontrolled by the controller 4 in this way, whereby the opticalmodulation element portions of all of the pixels in the display panelunit 2 are set to the initial state. In other words, the initial stateis set so that: (1) the optical modulation element portion of the pixelin the display panel unit 2 corresponding to a pixel having a pixelvalue of “0” as the pixel value of the B component image in the firstframe shifts to a state where the shutter is closed; and (2) the opticalmodulation element portion of the pixel in the display panel unit 2corresponding to a pixel having a pixel value of not “0” as the pixelvalue of the B component image in the first frame shifts to a statewhere the shutter is open.

(Period from t31 to t33):

At time t31, the controller 4 outputs, to the backlight unit 1, thebacklight control signal CTL_BL that instructs the backlight unit 1 to,turn on the light source (the light source that emits blue color light),so as to shift to a state where blue color light is projected. Based onthe backlight control signal CTL_BL from the controller 4, the backlightunit 1 turns on the light source (the light source that emits blue colorlight) of the backlight unit 1. This state (the state where the lightsource of blue color light is turned on so that the blue color light isemitted) is maintained during a period from t31 to t4.

At time t31, the segmented gate driver GD11 outputs a gate drivingsignal via the gate line GL1 so as to turn on the switching element SW1.Then, the source driver 3 outputs a source driving signal (a sourcedriving voltage V_S1) via the source line S1 during the period from t31to t32 so that the source driving electric current flows through theswitching element SW1 and the resistance R1. This allows the opticalmodulation element portion MS1 of the first pixel Px1 in the segmentedpixel region AR11 maintains the state where the shutter portion st1 isopen during the period from t31 to t32.

At time t32, the source driver 3 stops the output of the source drivingsignal (for example, shifts the source driving voltage VS1 to 0V), so asto cause the first electrode ex1 of the optical modulation elementportion MS1 of the first pixel Px1 to have a potential of 0V (the GNDpotential). This causes the attractive force exerted between the firstelectrode ex1 and the shutter portion st1 charged negatively todisappear, whereby the shutter portion st1 returns to the stateillustrated in FIG. 3, and the optical modulation element portion MS1 ofthe first pixel Px1 shifts to the state where the shutter is closed.

Here, the period from t31 to t32 and the period from t31 to t33 have thefollowing relationship in a case where the gray level value and theamount of light are in a relation of proportion:

(Period from t31 to t32)/(Period from t31 to t33)= 128/255

As described above, with a controlling operation that causes, in thefirst pixel Px1, a state where the shutter is open is maintained onlyduring the period from t31 to t32, and the blue color light is projectedfrom the first pixel Px1 to outside, a B component gray level value of“128” can be expressed at the first pixel Px1.

(Period from t33 to t35):

At time t33, the segmented gate driver GD11 outputs the gate drivingsignal so that the switching element SW2 is turned on, via the gate lineGL1. During a period from time t31 to time t35, the segmented gatedriver GD11 may output the gate driving signal so that the switchingelements SW1, SW2 are turned on, via the gate line GL1.

The source driver 3 outputs the source driving signal (the sourcedriving voltage V_S2) via the source line S2 during a period from t33 tot34, so that a source driving electric current flows through theswitching element SW2 and a resistance R2 (a resistance R2 (notillustrated) that is connected to the drain of the switching element SW2and the first electrode ex1 of the second pixel Px2, with the sameconfiguration as that of FIG. 3). This causes the optical modulationelement portion MS2 of the second pixel Px2 in the segmented pixelregion AR11 to maintain the state where the shutter portion st1 is open,during the period from t33 to t34.

At time t34, the source driver 3 stops the output of the source drivingsignal (for example, shifts the source driving voltage V_S2 to 0V), soas to cause the first electrode ex1 of the optical modulation elementportion MS2 of the second pixel Px2 to have a potential of 0V (the GNDpotential). This causes the attractive force exerted between the firstelectrode ex1 and the shutter portion st1 charged negatively disappear,whereby the shutter portion st1 returns to the state illustrated in FIG.3, and the optical modulation element portion MS1 of the second pixelPx2 shifts to the state where the shutter is closed.

Here, the period from t33 to t34 and the period from t33 to t35 have thefollowing relationship in a case where the gray level value and theamount of light are in a relation of proportion:

(Period from t33 to t34)/(Period from t33 to t35)= 53/255

As described above, with a controlling operation that causes, in thesecond pixel Px2, a state where the shutter is open is maintained onlyduring the period from t33 to t34, and the blue color light is projectedfrom the second pixel Px2 to outside, a B component gray level value of“53” can be expressed at the second pixel Px2.

Likewise, controlling operations identical to that described above areperformed so that predetermined B component gray level values areexpressed at the third pixel Px3 and the fourth pixel Px4 in thesegmented pixel region AR11.

Further, controlling operations identical to that described above areperformed so that predetermined B component gray level values areexpressed at the first to fourth pixels in the segmented pixel regionAR12, the first to fourth pixels in the segmented pixel region AR13, andthe first to fourth pixels in the segmented pixel region AR1m.

Thus, the driving with respect to the pixels on the first line of thedisplay panel unit 2 is completed.

Next, the pixels on the second line are driven by identical controllingoperations.

More specifically, controlling operations identical to that describedabove are performed so that predetermined B component gray level valuesare expressed at the fifth to eights pixels in the segmented pixelregion AR11 the fifth to eight pixels in the segmented pixel regionAR12, . . . and the fifth to eighth pixels in the segmented pixel regionAR1m.

Likewise, the pixels on the third and fourth lines is driven byperforming controlling operations identical to that described above inthe segmented pixel regions AR21 to AR2m.

The same processing is applied to the subsequent lines, whereby all ofthe pixels in the display panel unit 2 are driven in the same manner.With this, during the third subframe period from t3 to t4, the Bcomponent subframe image is displayed by the display panel unit 2.

The processing of the frames subsequent to the second frame is performedin the same manner, whereby a frame image (video image) is displayed onthe display panel unit 2 of the display device 1000.

As described above, the display device 1000 has such a configurationthat the segmented gate drivers GD11 to DGnm thus segmented are arrangedon the display panel unit 2. In the display device 1000, therefore, thelengths of the gate lines connected to the respective segmented gatedrivers GD11 to DGnm can be significantly decreased, as compared withthe lengths of the gate lines connected to the conventional gate driver(the length equivalent to pixels of about one line of the display panelunit).

In a case of a conventional gate driver, since the gate lines are long,the signal delay of the gate pulse signal and the waveform distortion(waveform roundness) had to be improved by reducing the time constantsof circuits formed with a gate driver, lines, and pixels, or increasingthe gate driving voltage of the gate driver. In contrast, in the case ofthe display device 1000, the length of the gate lines connected to therespective segmented gate drivers GD11 to DGnm can be set tosignificantly smaller as compared with the conventional cases, whichallows a gate pulse signal (gate driving signal) having reduced signaldelay or reduced waveform distortion (waveform roundness) to be outputfrom the respective segmented gate drivers GD11 to DGnm with a lowvoltage. As a result, in the display device 1000, the electric powerconsumption in the gate driving control can be reduced, which allows theelectric power consumption in the display device 1000 to be reduced aswell.

Further, in the display device 1000, since the gate driver is arrangedas the segmented gate drivers GD11 to DGnm within the display panel unit2, it is not necessary to provide a space for providing a gate driveroutside the display panel unit 2, which is different from theconventional display device. In the display device 1000, therefore, byproviding the segmented gate drivers GD11 to DGnm within the displaypanel unit 2, the peripheral region (frame region) of the display panelunit 2 can be reduced in size.

Embodiment 2

The following description describes Embodiment 2.

In the following description, parts characteristic of the presentembodiment are described, and detailed descriptions of parts identicalto those in the above-described embodiment are omitted.

FIG. 7 illustrates a schematic configuration of a display device 2000 ofEmbodiment 2.

The display device 2000 of Embodiment 2 has a configuration identical tothat of the display device 1000 of Embodiment 1 except that thecontroller 4 is replaced with a controller 4A and the source driver 3 isreplaced with a source driver 3A, as illustrated in FIG. 7.

The controller 4A has a function identical to that of the controller 4of Embodiment 1, and further, outputs an area setting signal set AR tothe source drive 3.

The controller 4A, for example, longitudinally segments the pixel areaof the display panel unit 2 as illustrated in FIG. 7, thereby settinglongitudinally segmented areas A1 to Am. Then, the controller 4Agenerates a signal containing information about the longitudinallysegmented areas A1 to Am as an area setting signal set AR, Thecontroller 4A outputs the generated area setting signal set AR to thesource driver 3A.

The longitudinally segmented area Ak natural number, 1≦k≦m) includessegmented pixel regions AR1k to ARnk, as illustrated in FIG. 7.

The source driver 3A has a function identical to that of the sourcedriver 3 of Embodiment 1, and further, inputs the area setting signalset AR output from the controller 4A. Based on the area setting signalset AR, the source driver 3A generates a source driving signal fordriving each longitudinally segmented area A1 to Am of the display panelunit 2, and outputs the same via the source lines.

The following description describes a case where, for example, displaycolors of the longitudinally segmented areas are set as described below.

(1) The number of colors displayed in the longitudinally segmented areaA1 is 27, the number of gray levels of the R component value is “3”, thenumber of gray levels, of the G component value is “3”, and the numberof gray levels of the B component value is “3”.

(2) The number of colors displayed in the longitudinally segmented areasA2 to A3 is 64, the number of gray levels of the R component value is“4”, the number of gray levels of the G component value is “4”, and thenumber of gray levels of the B component value is “4”.

(3) The number of colors displayed in the longitudinally segmented areasA4 to Am is 16777216, the number of gray levels of the R component valueis “256”, the number of gray levels of the G component value is “256”,and the number of gray levels of the B component value is “256”.

In the above-described case, when (1) the highest frequency f1 of asource driving signal for driving the longitudinally segmented area A1,(2) the highest frequency f2 of a source driving signal for driving thelongitudinally segmented areas A2 to A3, and (3) the highest frequencyf3 of a source driving signal for driving the longitudinally segmentedareas A4 to Am are assumed, the source driver 3A generates a sourcedriving signal in such a manner that the following is satisfied:

f1=( 3/256)×f3,

f2=( 4/256)×f3,

f3=1/T1, and

T1: time period having a duration of 1/256 of the duration of the periodfrom t1 to t13 in FIG. 5

In other words, for a pixel region where the number of colors to bedisplayed is small, a source driving signal is generated with a lowerdriving frequency, whereby the electric power consumption of the displaydevice 2000 can be reduced. In the display device 2000, the gray levelvalue of the pixel of a display image is expressed by the length of theopen/close time of the shutter portion st1 in the optical modulationelement portion. Therefore, when many gray level values are to beexpressed, it is necessary to control the open/close time of the shutterportion st1 in the optical modulation element portion with a drivingsignal having a higher frequency. On the other hand, when fewer graylevel values are to be expressed, the open/close time of the shutterportion st1 can be controlled in the optical modulation element portionwith a driving signal having a lower frequency, which allows theelectric power consumption to be reduced.

In the display device 2000 of the present embodiment, the number of graylevels to be expressed in each pixel region can be figured outpreliminarily, and the highest frequency of the source driving signalcan be set according to the number of gray levels to be expressed. Inother words, in the display device 2000, a pixel region in which thenumber of gray levels to be expressed is small can be driven with asource driving signal having a lower highest frequency, and therefore,the electric power consumption in the display device 2000 can bereduced.

The segmenting method for setting the longitudinally segmented areas isnot limited to the above-described segmenting method (the segmentingmethod illustrated in FIG. 7), and the longitudinally segmented areasmay be set by another segmenting method. For example, the longitudinallysegmented areas A1 and A2 in FIG. 7 may be set as one longitudinallysegmented area, and likewise, the longitudinally segmented areas Ak andAk+1 in FIG. 7 may be set as one longitudinally segmented area. Further,for example, an arbitrary number of longitudinally segmented areas amongthe longitudinally segmented areas A1 to Am in FIG. 7 may be set as onesegmented area.

Embodiment 3

The following description describes Embodiment 3.

In the following description, parts characteristic of the presentembodiment are described, and detailed descriptions of parts identicalto those in the above-described embodiments are omitted.

FIG. 8 illustrates a schematic configuration of a display device 3000 ofEmbodiment 3.

The display device 3000 of Embodiment 3 has a configuration identical tothat of the display device 2000 of Embodiment 2 except that thecontroller 4A is replaced with a controller 4B and the source driver 3Ais replaced with a source driver 3B, as illustrated in FIG. 8.

The controller 4B has a function identical to that of the controller 4Aof Embodiment 2. The controller 4B outputs gate control signals that aregenerated for respective horizontally segmented areas, to the displaypanel unit 2, as illustrated in FIG. 8. The present embodiment isdescribed by referring to an exemplary case where, as illustrated inFIG. 8, the pixel region is segmented into two in the horizontaldirection so that horizontally segmented areas AA1 and AA2 are set.

The controller 4B outputs, to the display panel unit 2, a gate controlsignal CTL_G1 for controlling segmented gate drivers GD11 to GDkmincluded in a horizontally segmented area AA1, and a gate control signalCTL_G2 for controlling segmented gate drivers GDq1 to GDnm included in ahorizontally segmented area AA2.

The subscripts k and q are natural numbers satisfying:

q=k+1, and

n=2×k.

The source driver 3A has a function identical to that of the sourcedriver 3A of Embodiment 2. Further, the source driver 3B is connected toa source line S1a for driving segmented pixel regions AR11 to ARk1 inthe horizontally segmented area AA1, and a source line S1b for drivingsegmented pixel regions ARq1 to ARn1 in the horizontally segmented areaAA2. The source driver 3B is capable of outputting source drivingsignals to the source line S1a and the source line S1b independently.The source driver 38, therefore, is capable of outputting source drivingsignals for driving the segmented pixel regions AR11 to ARk1 via thesource line S1a, while outputting source driving signals for driving thesegmented pixel regions ARq1 to ARn1 via the source line S1b.

Further, the source driver 3B is connected to a source line S2a fordriving the segmented pixel regions AR12 to ARk2 in the horizontallysegmented area AM, and a source line S2b for driving the segmented pixelregions ARq2 to ARn2 in the horizontally segmented area AA2. The sourcedriver 3B is capable of outputting source driving signals to the sourceline S2a and the source line S2b independently The source driver 38,therefore, is capable of outputting source driving signals for drivingthe segmented pixel regions AR12 to ARk2 via the source line S2a, whileoutputting source driving signals for driving the segmented pixelregions ARq2 to ARn2 via the source line S2b.

Likewise the source driver 38 is connected to source lines Sja fordriving the segmented pixel regions AR1j to ARkj (j: natural number,1≦j≦m) in the horizontally segmented area AA1, and source lines Sjb fordriving the segmented pixel regions ARqj to ARnj in the horizontallysegmented area AA2. The source driver 3B is capable of outputting sourcedriving signals to the source lines Sja and the source lines Sjbindependently. The source driver 36, therefore, is capable of outputtingsource driving signals for driving the segmented pixel regions AR1j toARkj via the source lines Sja, while outputting source driving signalsfor driving the segmented pixel regions ARqj to ARnj via the sourcelines Sjb.

In this way, in the display device 3000, the horizontally segmented areaAA1 and the horizontally segmented area AA2 can be driven in parallel bythe source driver 38.

With this configuration, in the display device 3000, a period of time(the periods from t1 to t11 and from t2 to t21 in FIG. 5, as well as theperiods from t3 to t31 and from t4 to t41 in FIG. 6) for setting theoptical modulation element portions of all of the pixels in the displaypanel unit 2 to the initial state can be decreased.

For example, in the display device 1000 in Embodiment 1, in order to setthe optical modulation element portions of all of the pixels in thedisplay panel unit 2 to the initial state, it is necessary to performgate driving with respect to all of the lines line-sequentially. Thegate driving time in this case is assumed to be “tg1”.

In the display device 3000 in the present embodiment, the gate drivingof the horizontally segmented area AA1 can be performed with the gatecontrol signal CTL_G1, and at the same time, the gate driving of thehorizontally segmented area M2 can be performed with the gate controlsignal CTL_G2. In other words, in the display device 3000, the gatedriving of the horizontally segmented area AA1 and the gate driving ofthe horizontally segmented area AA2 can be simultaneously performed inparallel.

In the display device 3000, therefore, in order to set the opticalmodulation element portions of all of the pixels in the display panelunit 2 to the initial state, the gate driving of the lines included inthe horizontally segmented area AA1 may be performed line-sequentially,and simultaneously, the gate driving of the lines included in thehorizontally segmented area AA2 may be performed line-sequentially.

In other words, in the display device 3000, the period of time requiredfor setting the optical modulation element portions of all of the pixelsin the display panel unit 2 to the initial state can be assumed to betg1/2.

With this configuration, the time of period for which the light sourceof the backlight unit 1 is kept in the ON state can be set longer,whereby the light emission intensity of the light source of thebacklight unit 1 can be decreased, and hence, the electric powerconsumption of the backlight unit 1 can be reduced.

This is described below, with reference to FIG. 9.

FIG. 9 is a diagram for explaining a controlling operation in a casewhere regions segmented in the horizontal direction are set, and thegate driving is performed with respect to the regions segmented in thehorizontal direction simultaneously.

The left diagram in FIG. 9 is a timing chart that illustrates thebacklight control signal CTL_BL of the display device 1000 of Embodiment1, and the backlight control signal CTL_BL of the display device 3000 ofEmbodiment 3, with the time axes thereof coinciding with each other.

The upper right diagram in FIG. 9 illustrates image data Din and asource driving signal VS1 in a case where R=128 (an R component graylevel value of “128”) is displayed at a first pixel Px1 in the segmentedpixel region AR11 in the display device 1000 of Embodiment 1.

The right lower diagram in FIG. 9 illustrates image data Din and asource driving signal V_S1 in a case where R=128 (an R component graylevel value of “128”) is displayed at a first pixel Px1 in the segmentedpixel region AR11 in the display device 3000 of Embodiment 3.

As is clear from FIG. 9, in the display device 3000 of Embodiment 3, inorder to set the optical modulation element portions of all of thepixels of the display panel unit 2 to the initial state, it is possibleto perform the gate driving with respect to the lines included in thehorizontally segmented area AA1 line-sequentially, and at the same time,to perform the gate driving with respect to the lines included in thehorizontally segmented area AA2 line-sequentially. In the display device3000, therefore, the period of time required for setting the opticalmodulation element portions of all of the pixels in the display panelunit 2 to the initial state is half of the period of time of T0 requiredin the display device 1000, that is, T0/2.

Since the subframe period is constant, it is possible in the displaydevice 3000 to set the light emission time of the light source of thebacklight unit 1 longer, for the decrease in the period of time requiredfor setting the optical modulation element portions of all of the pixelsin the display panel unit 2 to the initial state. In the case of FIG. 9,the light emission time of the light source of the backlight unit 1 inthe display device 3000 is 1.5 times the light emission time T0 of thelight source of the backlight unit 1 in the display device 1000.

In the display device 3000, the shutter open/close time at each pixelalso can be set longer in proportion to this extension rate of the lightemission time of the backlight unit 1. For example, as illustrated inFIG. 9, in a case where R=128 (R component gray level value of “128”) isdisplayed at the first pixel in the segmented pixel region AR11, theshutter portion st1 of the optical modulation element portion may bekept in an open state during a period of 0.75×T1, and the shutterportion st1 of the optical modulation element portion may be kept in aclosed state during a period of 0.75×T1. In other words, in the displaydevice 3000, the shutter open/close time at each pixel can be set to 1.5times as that of the shutter open/close time at each pixel in the caseof the display device 1000.

In this way, in the display device 3000, the shutter open/close time ateach pixel can be set longer, whereby the light emission intensity ofthe light source of the backlight unit 1 can be reduced, as comparedwith the display device 1000 of Embodiment 1 (in order to express acertain gray level value, the amount of projected light during aconstant period may be set to a predetermined amount, and hence, thelight emission intensity of the light source of the backlight unit 1 canbe reduced, for the increase in the period of time while the shutter ateach pixel is opened during a constant period). As a result, theelectric power consumption of the backlight unit 1 can be reduced.Further, as is clear from FIG. 9, the frequency of the source drivingsignal can be lowered, whereby the electric power consumption during thesource driving can be reduced.

As described above, in the display device 3000, regions segmented in thehorizontal direction are set, and the gate driving is performed withrespect to the regions segmented in the horizontal directionsimultaneously, whereby the electric power consumption of the backlightunit 1 can be reduced, and further, the frequency of the source drivingsignal can be lowered. With this configuration, in the display device3000, the electric power consumption can be further reduced.

The method for setting the regions segmented in the horizontal directionis not limited to the above-described method, but the regions segmentedin the horizontal direction may be set by another method, with anothernumber of segmented regions.

Further, in a case where the regions segmented in the horizontaldirection are segmented equally into k (k: natural number) and aredriven in parallel, the extension rate of the light emission time of thebacklight unit 1 is (2−1/k) times, Here, it is assumed that the periodof time for setting the optical modulation element portions of all ofthe pixels in the display panel unit 2 to the initial stateline-sequentially without parallel driving is 50% of one subframe timeThen, in the display device 3000, the shutter open/close time at eachpixel also can be set longer in proportion to this extension rate of thelight emission time of the backlight unit 1. In other words, as thenumber of the segmented regions driven in parallel is increased, theextension rate of light emission time of the backlight unit 1 alsoincreases, whereby the shutter open/close time at each pixel can be setlonger.

Other Embodiments

Part of or all of the above-described embodiments may be used incombination so that a display device is realized.

Further, the configuration of the MEMS shutter of the opticalmodulation, element portion in the embodiments described above is oneexample, and the optical modulation element portion may be formed byusing a MEMS shutter of another configuration.

Further, a part of an entirety of the touch-panel-equipped displaydevice of the above-described embodiments may be realized as anintegrated circuit (for example, an LSI, a system LSI, or the like).

A part or an entirety of a processing operation of each function blockof the above-described embodiments may be realized with programs. A partor an entirety of a processing operation of each function block of theabove-described embodiments may be executed by a central processing unit(CPU) in a computer. Further, the programs for executing the respectiveprocessing operations may be stored in a storage device such as a harddisk or a ROM, and the central processing unit (CPU) may read theprograms from a ROM or a RAM and execute the same.

Further, each processing operation in the above-described embodimentsmay be realized with hardware, or may be realized with software(including a case of being realized together with an operating system(OS)), middleware, or a predetermined library). Further alternatively,each processing operation may be realized with software and hardware incombination.

Still further, the order of execution of operations in the processingmethod in the above-described embodiments is not limited to that in theabove-described embodiments. The order can be changed without deviatingfrom the scope of the invention.

A computer program that causes a computer to execute the above-describedmethod, and a computer-readable recording medium in which the program isrecorded, are encompassed in the scope of the present invention. Here,examples of the computer-readable recording medium include a flexibledisk, a hard disk, a CD-ROM, an MO, a DVD, a large-capacity DVD, anext-generation DVD, and a semiconductor memory.

The above-described computer program is not limited to a programrecorded in, the above-described recording medium, but may be a programthat is transmitted through a network or the like that is typically, forexample, an electric communication channel, a wireless or wiredcommunication channel, or the Internet.

Still further, in part of the descriptions of the above-describedembodiments, only principal members essential for the above-describedembodiments, among the constituent members, are, described in asimplified manner. The configurations of the above-described embodimentscan include arbitrary constituent members that are not clearly mentionedin the descriptions of the embodiments. Further, in the descriptions andthe drawings of the above-described embodiments, some of the respectivesizes of the members do not faithfully represent the real sizes, thereal dimension ratios, and the like.

The specific configuration of the present invention is not limited tothe configurations of the above-described embodiments, but can bevariously changed and modified without deviating from the scope of theinvention.

[Supplementary Note]

The present invention can be also described as follows.

The first invention is a display device that includes a backlight unit,a display panel unit, a source driver, and a controller.

The backlight unit includes a light source.

The display panel unit includes a plurality of first segmented regions,each of the first segmented regions including: a plurality of pixelseach of which includes an optical modulation element that performsmodulation control with respect to light emitted from the backlightunit; and a segmented gate driver for controlling the optical modulationelements of the pixels.

The source driver is a driver for controlling the optical modulationelements of the pixels.

The controller controls the light source, the segmented gate drivers,and the source driver.

This display device has such a configuration that the segmented gatedrivers thus segmented are arranged in the display panel unit. In thisdisplay device, therefore, the lengths of the gate lines connected tothe respective segmented gate drivers can be significantly decreased, ascompared with the lengths of the gate lines connected to theconventional gate driver (the length equivalent to pixels of about oneline of the display panel unit).

In other words, in the case of this display device, the lengths of thegate lines connected to the respective segmented gate drivers can besignificantly decreased as compared with the conventional cases, whichallows a gate pulse signal (gate driving signal) having reduced signaldelay or reduced waveform distortion (waveform roundness) to be outputfrom the respective segmented gate drivers with a low voltage. As aresult, in the display device, the electric power consumption in thegate driving control can be reduced, which allows the electric powerconsumption in the display device to be reduced as well.

Further, in the display device, since the gate driver is arranged as thesegmented gate drivers within the display panel unit, it is notnecessary to provide a space for providing a gate driver outside thedisplay panel unit, which is different from the conventional displaydevice. In the display device, therefore, by providing the segmentedgate drivers within the display panel unit, the peripheral region (frameregion) of the display panel unit can be reduced in size.

The second invention is the first invention in which the controllergenerates a second segmented region setting signal for setting secondsegmented regions by segmenting the pixels of the display panel unitaccording to the number of gray levels to be displayed, and outputs thegenerated second segmented region setting signal o the source driver.

The source driver sets a highest frequency of the source driving signalfor driving the pixels included in the second segmented regions based onthe second segmented region setting signal, and drives the pixelsincluded in the second segmented regions with the source driving signalhaving the highest frequency thus set.

With this configuration, in this display device, the number of graylevels to be expressed in each pixel region (each second segmentedregion) can be figured out, and the highest frequency of the sourcedriving signal can be set according to the number of gray levels to beexpressed. In other words, in this display device, a pixel region (asecond segmented region) in which the number of gray levels to beexpressed is small can be driven with a source driving signal having alower highest frequency, and therefore, the electric power consumptionin this display device can be reduced.

The third invention is the first or second invention in which thecontroller sets k third segmented regions AR(1) to AR(k) in which thepixels of the display panel unit are segmented per one or a plurality ofscanning lines, generates gate control signals SG(1) to SG(k) forcontrolling gate driving with respect to the pixels included in thethird segmented regions AR(1) to AR(k) so that the gate control signalsSG(1) to SG(k) correspond to the third segmented regions AR(1) to AR(k),respectively, and outputs the generated gate control signals SG(1) toSG(k) to the segmented gate drivers corresponding thereto, respectively.

Then, the controller respectively drives the segmented gate driverscorresponding to the gate control signals SG(1) to SG(k) in parallel.

In this display device, since the gate driving can be performedsimultaneously with respect to the regions (third segmented regions)thus segmented into k, the period of time required for setting theoptical modulation element portions of all of the pixels of the displaypanel unit to the initial state can be decreased (can be decreased toabout 1/k). In this display device, the light emission time of the lightsource of the backlight unit can be set longer, for the decrease in theperiod of time required for setting the optical modulation elementportions of all of the pixels in the display panel unit to the initialstate, and in proportion to this, the open/close time of the shutter ofthe optical modulation element portion of each pixel can be set longer.

Since the shutter open/close time at each pixel can be set longer inthis display device in this way, it is possible to reduce the lightemission intensity of the light source of the backlight unit, ascompared with conventional cases. As a result, in this display device,the electric power consumption of the backlight unit can be reduced.Further, since the shutter open/close time at each pixel can be setlonger in this display device, the frequency of the source drivingsignal can be lowered. As a result, in this display device, the electricpower consumption during the source driving can be reduced.

The fourth invention is any one of the first to third inventions inwhich the optical modulation element is a microelectromechanical system(MEMS) device.

With this configuration, a display device can be realized with use ofMEMS devices as optical modulation elements.

INDUSTRIAL APPLICABILITY

With the present invention, a display device can be realized in whichthe electric power consumption when optical modulation elements (forexample, MEMS shutters) are driven can be reduced. The present inventionis therefore useful in the field of the display-device-related industry,and can be implemented in this field.

DESCRIPTION OF REFERENCE NUMERALS

1000, 2000, 3000 display device1 backlight unit2 display panel unit3, 3A, 3B source driver4, 4A, 4B controllerGD11 to GDnm segmented gate driver

What is claimed is:
 1. A display device comprising: a backlight unitthat includes a light source; a display panel unit that includes aplurality of first segmented regions, each of the first segmentedregions including: a plurality of pixels each of which includes anoptical modulation element that performs modulation control with respectto light emitted from the backlight unit; and a segmented gate driverthat controls the optical modulation elements of the pixels; a sourcedriver that controls the optical modulation elements of the pixels; anda controller that controls the light source, the segmented gate drivers,and the source driver.
 2. The display device according to claim 1,wherein the controller generates a second segmented region settingsignal for setting second segmented regions by segmenting the pixels ofthe display panel unit according to the number of gray levels to bedisplayed, and outputs the generated second segmented region settingsignal to the source driver, and the source driver sets a highestfrequency of the source driving signal for driving the pixels includedin the second segmented regions based on the second segmented regionsetting signal, and drives the pixels included in the second segmentedregions with the source driving signal having the highest frequency thusset.
 3. The display device according to claim 1, wherein the controllersets k third segmented regions AR(1) to AR(k) in which the pixels of thedisplay panel unit are segmented per one or a plurality of scanninglines, generates gate control signals SG(1) to SG(k) for controllinggate driving with respect to the pixels included in the third segmentedregions AR(1) to AR(k) so that the gate control signals SG(1) to SG(k)correspond to the third segmented regions AR(1) to AR(k), respectively,and outputs the generated gate control signals SG(1) to SG(k) to thesegmented gate drivers corresponding thereto, respectively, andrespectively controls the segmented gate drivers corresponding to thegate control signals SG(1) to SG(k) in parallel.
 4. The display deviceaccording to claim 1, wherein the optical modulation element is amicroelectromechanical system (MEMS) device.